Abstract: An aircraft with an aft-fuselage propulsion system comprises a thermal engine, a first electric motor coupled to a first propulsor, a second electric motor coupled to a second propulsor, and a mechanical interlink system integrating the thermal engine, the first electric motor, the second electric motor, plural battery systems and associated power electronics, and cabling elements connecting the electric machines. An aircraft has plural mirrored aft-fuselage propulsion systems, each aft-fuselage propulsion system comprising a thermal engine, an electric motor, a propulsor, and a mechanical interlink system integrating the thermal engine, electric motor, and propulsor elements.

Abstract: For aircraft taxiing, an aircraft is equipped with an electric machine installed in a propulsor gearbox (PGB), in parallel to the gas turbine, working in motor mode during taxi, and in generator mode during flight phases (such as take-off, climb, cruise, descent, approach and landing). Typical current systems which use an electric machine in the PGB do not use the electric machine in motor mode for taxi operations (i.e., it is only an additional generator). An optimized power supply providing a combination of a thermal engine such as an Auxiliary Power Unit (APU) and an electric energy storage system such as a battery provides power to the PGB electric machine even when the gas turbine is off.

Abstract: Unmanned aircraft have aligned forward and aft propulsion systems possessing different performance and/or noise characteristics. According to some embodiments, unmanned aircraft have a forward engine and a forward tractor propeller and an aft engine and an aft pusher propeller. Selected ones of forward and aft propulsion systems will thus be provided to have greater and lesser operational flight performance characteristics and greater and lesser noise signature characteristics, respectively, as compared to the other. For example, the forward propulsion system may be provided with the greater operational flight performance and higher signature characteristics as compared to the aft propulsion system, while conversely the aft propulsion system may be provided with a lesser flight performance and lower noise signature characteristics as compared to the forward propulsion system.

Abstract: An aircraft stores cryogenic fuel in one or more fuel tanks inside the aircraft fuselage or at other appropriate positions on the aircraft, and stores non-cryogenic fuel in plural standard jet fuel tanks e.g., inside the aircraft wings. A controller controls selective routing of non-cryogenic fuel or cryogenic (e.g., hydrogen) fuel to dual fuel engines. In one operating mode, the dual fuel engines normally use the cryogenic hydrogen fuel as the main fuel, and reserve the non-cryogenic fuel for application to the dual fuel engines only on an exception basis, thereby providing cleaner and more environmentally friendly operation.

Abstract: An aircraft with the capability of taxiing with main engines off uses the energy stored in a mechanical flywheel to power a propulsor(s) providing taxiing thrust. The flywheel can store energy generated by the propulsor operating as a wind turbine and/or by a power turbine in fluid coupling with the exhaust of a gas turbine engine and/or an expansion turbine operating with bleed and/or APU air.

Abstract: An aircraft with the capability of taxiing with main engines off uses the energy stored in a mechanical flywheel to power a propulsor(s) providing taxiing thrust. The flywheel can store energy generated by the propulsor operating as a wind turbine and/or by a power turbine in fluid coupling with the exhaust of a gas turbine engine and/or an expansion turbine operating with bleed and/or APU air.

Abstract: Unmanned aircraft have aligned forward and aft propulsion systems possessing different performance and/or noise characteristics. According to some embodiments, unmanned aircraft have a forward engine and a forward tractor propeller and an aft engine and an aft pusher propeller. Selected ones of forward and aft propulsion systems will thus be provided to have greater and lesser operational flight performance characteristics and greater and lesser noise signature characteristics, respectively, as compared to the other. For example, the forward propulsion system may be provided with the greater operational flight performance and/or noise signature characteristics as compared to the aft propulsion system, while conversely the aft propulsion system may be provided with a lesser flight performance and/or noise signature characteristics as compared to the forward propulsion system.

Abstract: For aircraft taxiing, an aircraft is equipped with an electric machine installed in a propulsor gearbox (PGB), in parallel to the gas turbine, working in motor mode during taxi, and in generator mode during flight phases (such as take-off, climb, cruise, descent, approach and landing). Typical current systems which use an electric machine in the PGB do not use the electric machine in motor mode for taxi operations (i.e., it is only an additional generator). An optimized power supply providing a combination of a thermal engine such as an Auxiliary Power Unit (APU) and an electric energy storage system such as a battery provides power to the PGB electric machine even when the gas turbine is off.